Question

Find the sum of the geometric sequence -3,15,-75,375,... when there are 7 terms and select the correct answer below.

Answer 1

-39,063

Explanation:

In this geometric, sequence, you are multiplying by -5. So, we can continue the sequence by mulitplying 375(your last value) by -5 and so on, until we have 7 total terms.

Now we add the terms together:

-3+15+-75+375+-1875+9375+-46875

=-3+15-75+375-1875+9375-46875

=-39063

Hope this helps :)